Touch panel system and electronic device

ABSTRACT

In a touch panel system ( 1 ) of the present invention, a stylus pen ( 3 ) produces output that indicates that a quantitative characteristic value is increased from the characteristic value of a previous output by using a waveform that corresponds to an (L+1)-th drive line (DL L+1 ) other than L numbers of drive lines (DL 1  to DL L ) and, meanwhile, produces output that indicates that the quantitative characteristic value is decreased from the characteristic value of the previous output by using a waveform that corresponds to an (L+2)-th drive line (DL L+2 ) other than the L numbers of drive lines (DL 1  to DL L ). A touch panel controller ( 10 ) includes a conversion output unit ( 19 ) that converts and outputs the quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs×the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive line (DL L+1 ) or in the waveform that corresponds to the (L+2)-th drive line (DL L+2 ).

TECHNICAL FIELD

The present invention relates to a touch panel system and an electronicdevice that detect the position of the touch of a touch pen on a touchpanel which has electrostatic capacitances formed at each intersectionof a plurality of first signal lines and a plurality of second signallines. Specifically, the invention relates to a method for coping with acase where there are many types of information of an electronic pen whena touch pen is configured of an electronic pen that signals can be inputinto and output from.

BACKGROUND ART

In the related art, there is known, for example, a touch panel systemdisclosed in PTL 1 as a touch panel system that detects the position ofthe touch of a touch pen on a touch panel which has electrostaticcapacitances formed at each intersection of a plurality of first signallines and a plurality of second signal lines.

The touch panel system disclosed in PTL 1 includes a plurality ofelectronic pens, a panel main body that includes a touch face on which atouch operation is performed by the electronic pens and a finger and inwhich a plurality of transmission electrodes that runs parallel to eachother and a plurality of reception electrodes that runs parallel to eachother are arranged into a lattice, a transmission unit that applies adrive signal to the transmission electrodes, a reception unit thatreceives a response signal which is output from the reception electrodesin response to the drive signal applied to the transmission electrodesand outputs detection data for each intersection of the electrodes, anda control unit that detects the position of a touch on the basis of thedetection data which is output from the reception unit, in which thetransmission unit applies a pen synchronization signal that synchronizesthe transmission and reception of a pen identifiable signal between theelectronic pens and the reception unit to the transmission electrodes,the electronic pens transmit the pen identifiable signal to thereception electrodes in response to the detection of the pensynchronization signal in the transmission electrodes at the time of atouch operation, and the control unit, on the basis of the pensynchronization signal that the reception unit receives through thereception electrodes, identifies a pointed object on which a touchoperation is performed.

According to this configuration, a plurality of electronic pens can beused because each electronic pen transmits the pen identifiable signalto the reception electrodes in response to the detection of the pensynchronization signal from the transmission electrodes at the time of atouch operation and because the control unit, on the basis of the pensynchronization signal that the reception unit receives through thereception electrodes, identifies the electronic pen that performs thetouch operation.

When an electronic pen that is provided with additional functions suchas a pen pressure sensing function is used as the touch pen, it isnecessary to transmit information that the electronic pen obtains to thetouch panel controller.

In this case, for example, in the position detecting device disclosed inPTL 2, the electronic pen transmits information to the touch panelcontroller by using a signal that is configured of a plurality of typesof codes which have different code patterns.

CITATION LIST Patent Literature

PTL 1: Japanese Unexamined Patent Application Publication No.2012-022543 (published on Feb. 2, 2012)

PTL 2: Japanese Unexamined Patent Application Publication No.2011-164801 (published on Aug. 25, 2011)

SUMMARY OF INVENTION Technical Problem

In such identification methods of PTL 1 and PTL 2, however, a problemarises when there are many types of information that is transmitted fromthe electronic pen. The number of types of code patterns increases, and,in turn, information has to be transmitted by a code pattern that hasmany bit digits. Thus, the amount of signals increases, and theidentification of signals becomes complicated.

For example, when the electronic pen outputs a quantitativecharacteristic value such as in the case of representing a pen pressurevalue with 10 bits, it is necessary to assign 10 types of drive patternsto one electronic pen. In this case, more drive time is required insequential driving. In parallel driving, a decoding range becomes wide,or it is difficult to increase the number of electronic pens.

The present invention is devised with consideration of the problem inthe related art, and an object thereof is to provide a touch panelsystem and an electronic device that may simply transmit information ina short amount of time when an electronic pen that outputs aquantitative characteristic value having many types of information isused.

Solution to Problem

In order to resolve the problem, according to an aspect of the presentinvention, there is provided a touch panel system including a touch pen,a touch panel that has electrostatic capacitances formed at eachintersection of K (K is an integer greater than or equal to two) numbersof first signal lines and L (L is an integer satisfying L≧K) numbers ofsecond signal lines, and a touch panel controller, in which the touchpanel controller outputs drive signals that drive the K numbers of thefirst signal lines or the L numbers of the second signal lines from adrive unit through L numbers of drive signal lines and receives input ofdetection signals from the K numbers of the first signal lines or the Lnumbers of the second signal lines detected by a detecting unit throughL numbers of detection signal lines on the basis of a change in chargesthat is accumulated in the electrostatic capacitances due to the touchpen when the touch pen touches the touch panel, the touch pen isconfigured of an electronic pen that outputs a quantitativecharacteristic value, the electronic pen produces output that indicatesthat the quantitative characteristic value of the electronic pen isincreased from the characteristic value of a previous output by using awaveform that corresponds to an (L+1)-th drive signal line other thanthe L numbers of the drive signal lines and, meanwhile, produces outputthat indicates that the quantitative characteristic value of theelectronic pen is decreased from the characteristic value of theprevious output by using a waveform that corresponds to an (L+2)-thdrive signal line other than the L numbers of the drive signal lines,and the touch panel controller includes a conversion output unit thatconverts and outputs the quantitative characteristic value by using thesum of the initial value of the quantitative characteristic value andthe number of outputs×the unit amount of increase or decrease in thewaveform that corresponds to the (L+1)-th drive signal line or in thewaveform that corresponds to the (L+2)-th drive signal line.

The representation of L+1 and L+2 is for representing drive signal linesother than the L numbers or the K numbers of drive signal lines, meaningthat the drive signal lines are not actually connected to the touchpanel. Thus, when the actual number of connection lines between thetouch panel and the touch panel controller is less than L or K, awaveform that corresponds to an arbitrary drive signal line of thenon-connected drive signal lines may be used.

In order to resolve the problem, according to another aspect of thepresent invention, there is provided an electronic device including theabove touch panel system.

Advantageous Effects of Invention

According to the aspects of the present invention, the effect ofproviding a touch panel system and an electronic device that may simplytransmit information in a short amount of time when an electronic penthat outputs a quantitative characteristic value having many types ofinformation is used is achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a touch panel system in a first embodiment of thepresent invention and is a block diagram illustrating a configuration ofthe touch panel system.

FIG. 2 is an interconnect diagram illustrating a configuration of atouch panel disposed in the touch panel system.

FIG. 3 is a circuit diagram illustrating a configuration of amultiplexer that is used to switch a connection between a signal lineconnected to the touch panel and a drive line connected to a driver anda connection between the signal line and a sense line connected to asense amplifier.

FIG. 4 is a block diagram illustrating a configuration of a stylus penin the touch panel system.

FIG. 5 is a timing chart illustrating a basic operation that isperformed to synchronize the stylus pen.

FIG. 6(a) is a diagram illustrating an output relationship between thedrive line of the driver and the sense line of the sense amplifier inthe touch panel controller to the touch panel and the stylus pen, andFIG. 6(b) is a waveform diagram illustrating a synchronization waveformand a touch detection waveform.

FIG. 7(a) is a waveform diagram illustrating a drive waveform, such as asynchronization waveform and a touch detection waveform transmitted fromthe touch panel controller to the stylus pen, and a low-frequency noise,FIG. 7(b) is a waveform diagram illustrating a state where the drivewaveform and the low-frequency noise are superimposed, and FIG. 7(c) isa waveform diagram illustrating a state where the superimposed waveformis reset at reset timings.

FIG. 8 is a diagram illustrating a configuration of a reset circuitprovided in a synchronization signal detector circuit of the stylus pen.

FIG. 9(a) is a waveform diagram illustrating an example of asynchronization waveform transmitted from the touch panel controller,FIG. 9(b) is a waveform diagram illustrating an input waveform receivedby the stylus pen, FIG. 9(c) is a waveform diagram illustrating aninternal waveform when a reference potential is set at a reset timing R1in FIG. 9(b), and FIG. 9(d) is a waveform diagram illustrating aninternal waveform when a reference potential is set at a reset timing R2in FIG. 9(b).

FIG. 10(a) is a waveform diagram illustrating a synchronization waveformthat uses the M-sequence code “1110010” which is not Manchester-coded,and FIG. 10(b) is a waveform diagram illustrating a synchronizationwaveform that uses the Manchester-coded M-sequence code “1110010”.

FIG. 11(a) is a waveform diagram illustrating an example of asynchronization waveform that has a long High period and is transmittedfrom the touch panel controller, FIG. 11(b) is a waveform diagramillustrating a reset timing R3 of an input waveform received by thestylus pen, and FIG. 11(c) is a waveform diagram illustrating aninternal waveform when a reference potential is set at the reset timingR3 in FIG. 11(b).

FIG. 12(a) is a diagram illustrating a synchronization waveform of apseudorandom sequence that has periodicity, is Manchester-coded, and istransmitted to the stylus pen from the touch panel controller of thetouch panel system, and FIG. 12(b) is a waveform diagram illustratingthe synchronization waveform and a touch detection waveform.

FIG. 13 is an operation image diagram illustrating a correspondencebetween a drive operation of the touch panel controller and a driveoperation of the stylus pen.

FIGS. 14(a) to 14(c) are diagrams illustrating a specific driveoperation in a synchronization signal detection period, a pause period,and a normal drive period illustrated in FIG. 13.

FIG. 15 is a diagram illustrating a relationship between a drive patternof the driver in the touch panel controller and a drive pattern of adrive circuit in the stylus pen.

FIG. 16 is a diagram illustrating a pen pressure value that is obtainedin the stylus pen and a pen pressure value that is represented in thestylus pen having the pen pressure and in the touch panel controller.

FIG. 17 illustrates a touch panel system in a second embodiment of thepresent invention and is a block diagram illustrating a configuration ofthe touch panel system.

FIG. 18 is a diagram illustrating a pen pressure value when there is adifference among an actual pen pressure value of the stylus pen, a penpressure value that is updated and retained in the stylus pen, and a penpressure value that is represented in the touch panel controller.

FIG. 19 is a diagram illustrating a pen pressure value in the case ofincreasing or decreasing the unit amount of increase or decrease byproviding a continuous increase or decrease changing unit in a unitincrease or decrease amount changing unit of a conversion output unit inthe touch panel controller.

FIG. 20 is a diagram illustrating an example of a method for adjustingan inner pen pressure value in the stylus pen.

FIG. 21(a) is a waveform diagram illustrating an input waveform of asynchronization signal received by the stylus pen in a touch panelsystem in a third embodiment of the present invention, and FIG. 21(b) isa waveform diagram illustrating an internal waveform when a referencepotential is set at reset timings R1 to R6.

FIG. 22(a) is a waveform diagram illustrating an example of asynchronization waveform transmitted from the touch panel controller,FIG. 22(b) is a waveform diagram illustrating reset timings R7, R8, andR9 of an input waveform received by the stylus pen, and FIG. 22(c) is awaveform diagram illustrating a synchronization waveform when areference potential is set at the reset timings R7, R8, and R9illustrated in FIG. 22(b).

FIG. 23 is a timing chart illustrating output waveforms of the touchpanel controller in which a fixing period is disposed immediately beforea synchronization waveform is output.

FIG. 24(a) is a waveform diagram illustrating an example of asynchronization waveform transmitted from the touch panel controller,FIG. 24(b) is a waveform diagram illustrating reset timings R11, R12,and R13 of an input waveform received by the stylus pen, and FIG. 24(c)is a waveform diagram illustrating a synchronization waveform when areference potential is set at the reset timings R11, R12, and R13illustrated in FIG. 24(b).

FIG. 25(a) is a diagram illustrating a method for transmitting asynchronization waveform that is transmitted by drive lines DL₁ toDL_(L) of the driver in the touch panel controller, FIG. 25(b) is awaveform diagram illustrating an input waveform received by the styluspen, and FIG. 25(c) is a waveform diagram illustrating a synchronizationwaveform when a reference potential is set after the input waveform isinitially reset in the fixing period illustrated in FIG. 25(b).

FIG. 26 is an operation image diagram illustrating a correspondencebetween a drive operation of the touch panel controller and a driveoperation of the stylus pen.

FIG. 27 is a diagram illustrating a specific drive operation in thefixing period illustrated in FIG. 26.

FIG. 28 is a block diagram illustrating a configuration of a mobilephone that is provided with a touch panel system in a fourth embodimentof the present invention.

DESCRIPTION OF EMBODIMENTS First Embodiment

An embodiment of the present invention will be described as follows onthe basis of FIG. 1 to FIG. 16.

(Configuration of Touch Panel System)

A configuration of a touch panel system 1 of the present embodiment willbe described on the basis of FIG. 1 and FIG. 2. FIG. 1 is a blockdiagram illustrating a configuration of the touch panel system 1 of thepresent embodiment, and FIG. 2 is an interconnect diagram illustrating aconfiguration of a touch panel disposed in the touch panel system.

The touch panel system 1 of the present embodiment, as illustrated inFIG. 1, is provided with a touch panel 2, a stylus pen 3 as a touch penand an electronic pen, and a touch panel controller 10 that drives thetouch panel 2 and the stylus pen 3.

The touch panel 2, as illustrated in FIG. 2, is provided with horizontalsignal lines HL₁ to HL_(K) as K (K is a positive integer) numbers firstsignal lines that are plural lines arranged parallel to each other alongthe horizontal direction and vertical signal lines VL₁ to VL_(L) as L (Lis a positive integer) numbers of second signal lines that are plurallines arranged parallel to each other along the vertical direction.Electrostatic capacitances C11 to CKL are generated at each intersectionof the horizontal signal lines HL₁ to HL_(K) and the vertical signallines VL₁ to VL_(L). While K and L may be either the same or different,the present embodiment will be described on the assumption that L≧K. Inaddition, while the vertical signal lines VL₁ to VL_(L) verticallyintersect the horizontal signal lines HL₁ to HL_(K) in the presentembodiment, the present invention is not necessarily limited to this,provided that both intersect each other.

The touch panel 2, although preferably having a width such that a handholding the stylus pen 3 can be put on the touch panel 2, may have asize used in a smartphone.

The stylus pen 3, in the present embodiment, is not only a touch penthat is configured of a conductor and that is simply used for touchingthe touch panel 2 but also a pen that signals can be input into andoutput from. As described below, a synchronization signal detectorcircuit 36 is disposed in the stylus pen 3 so that a synchronizationsignal for synchronization with a dedicated synchronization signalgenerated by a timing generator 14 of the touch panel controller 10 isreceived and input into the stylus pen 3.

The touch panel controller 10, as illustrated in FIG. 2, is providedwith a multiplexer 11, a driver 12, a sense amplifier 13, the timinggenerator 14, an AD converter 15, capacitance distribution calculatingunit 16, a touch recognizing unit 17, and a pen position detecting unit18.

The driver 12 is configured to apply voltage to drive lines DL₁ toDL_(K) or to drive lines DL₁ to DL_(L) in correspondence with driving ofthe horizontal signal lines HL₁ to HL_(K) or driving of the verticalsignal lines VL₁ to VL_(L) in the touch panel 2.

The sense amplifier 13 reads a signal of initial charges and a linearsummation signal through sense lines SL₁ to SL_(L) and supplies thesignal and the linear summation signal to the AD converter 15. Theinitial charges of the signal correspond to each of the electrostaticcapacitances C11 to CKL of the touch panel 2 at the time of driving thehorizontal signal lines HL₁ to HL_(K) in a first signal line driveperiod. The linear summation signal corresponds to a first pen chargesignal that is charges at the time of a touch which correspond to theelectrostatic capacitances between the stylus pen 3 and each of the Lnumbers of the vertical signal lines VL₁ to VL_(L) at the time of atouch. That is, when the stylus pen 3 approaches a position on the touchpanel 2 while charges corresponding to each of the electrostaticcapacitances C11 to CKL are detected in the first signal line driveperiod, charges of the electrostatic capacitance at the position change.Thus, the changed changes of the electrostatic capacitance can bedetected as a linear summation signal. Usually, when the stylus pen 3approaches the touch panel 2, each of the electrostatic capacitances C11to CKL at the approached position increases.

The sense amplifier 13 is configured to read a signal of initial chargesand a linear summation signal through the sense lines SL₁ to SL_(K) andto supply the signal and the linear summation signal to the AD converter15. The initial charges of the signal correspond to each of theelectrostatic capacitances C11 to CKL of the touch panel 2 at the timeof driving the vertical signal lines VL₁ to VL_(L) in a second signalline drive period. The linear summation signal corresponds to a secondpen charge signal that is charges at the time of a touch whichcorrespond to the electrostatic capacitances between the stylus pen 3and each of the K numbers of the horizontal signal lines HL₁ to HL_(K)at the time of a touch.

Next, the multiplexer 11 will be described on the basis of FIG. 3. FIG.3 is a circuit diagram illustrating a configuration of a multiplexerthat switches connections between the horizontal signal lines HL₁ toHL_(K) or the vertical signal lines VL₁ to VL_(K) to VL_(L) disposed inthe touch panel 2 and the drive lines DL₁ to DL_(K) to DL_(L) connectedto the driver or the sense lines SL₁ to SL_(K) to SL_(L) connected tothe sense amplifier 13.

The multiplexer 11 is a connection switch circuit that switchesconnections between a plurality of inputs and a plurality of outputs. Inthe present embodiment, as illustrated in FIG. 3, the multiplexer 11switches between a first connection state where the horizontal signallines HL₁ to HL_(K) are connected to the drive lines DL₁ to DL_(K) ofthe driver 12 and where the vertical signal lines VL₁ to VL_(K) toVL_(L) are connected to the sense lines SL₁ to SL_(K) to SL_(L) of thesense amplifier 13 and a second connection state where the horizontalsignal lines HL₁ to HL_(K) are connected to the sense lines SL₁ toSL_(K) of the sense amplifier 13 and where the vertical signal lines VL₁to VL_(K) to VL_(L) are connected to the drive lines DL₁ to DL_(K) toDL_(L) of the driver 12.

In the multiplexer 11, when the signal of a control line CL illustratedin FIG. 3 is set to Low, the horizontal signal lines HL₁ to HL_(K) areconnected to the drive lines DL₁ to DL_(K), and the vertical signallines VL₁ to VL_(L) are connected to the sense lines SL₁ to SL_(L).Meanwhile, when the signal of the control line CL is set to High, thehorizontal signal lines HL₁ to HL_(K) are connected to the sense linesSL₁ to SL_(K), and the vertical signal lines VL₁ to VL_(L) are connectedto the drive lines DL₁ to DL_(L).

Next, the timing generator 14 illustrated in FIG. 1 generates a signalthat defines the operation of the driver 12, a signal that defines theoperation of the sense amplifier 13, and a signal that defines theoperation of the AD converter 15 and respectively supplies the signalsto the driver 12, the sense amplifier 13, and the AD converter 15. Inaddition, the timing generator 14 generates a synchronization signal.The touch panel controller 10 is configured to drive the horizontalsignal lines HL₁ to HL_(K) and the vertical signal lines VL₁ to VL_(L)by using the synchronization signal generated by the timing generator 14as a synchronization-dedicated signal.

Next, the AD converter 15, during the first signal line drive period,performs AD conversion on charges that correspond to each of theelectrostatic capacitances C11 to CKL and that are read through thevertical signal lines VL₁ to VL_(L) and through the sense lines SL₁ toSL_(L) and on the linear summation signal that corresponds to the firstpen charge signal which is charges corresponding to the electrostaticcapacitances between the stylus pen 3 and each of the L numbers of thevertical signal lines VL₁ to VL_(L). The AD converter 15 supplies theAD-converted charges and linear summation signal to the capacitancedistribution calculating unit 16.

The AD converter 15, during the second signal line drive period,performs AD conversion on charges that correspond to each of theelectrostatic capacitances C11 to CKL and that are read through thehorizontal signal lines HL₁ to HL_(K) and through the sense lines SL₁ toSL_(K) and on the linear summation signal that corresponds to the secondpen charge signal which is charges corresponding to the electrostaticcapacitances between the stylus pen 3 and each of the K numbers of thehorizontal signal lines HL₁ to HL_(K). The AD converter 15 supplies theAD-converted charges and linear summation signal to the capacitancedistribution calculating unit 16.

Next, the capacitance distribution calculating unit 16, on the basis ofthe linear summation signal that includes the first pen charge signaland the second pen charge signal and on the basis of a code sequencebased on driving, calculates the distribution of electrostaticcapacitances on the touch panel 2, the distribution of electrostaticcapacitances between the stylus pen 3 and each of the L numbers of thevertical signal lines VL₁ to VL_(L), and the distribution ofelectrostatic capacitances between the stylus pen 3 and each of the Knumbers of the horizontal signal lines HL₁ to HL_(K), supplies thedistribution of electrostatic capacitances on the touch panel 2 to thetouch recognizing unit 17, and supplies the distribution ofelectrostatic capacitances between the stylus pen 3 and each of the Lnumbers of the vertical signal lines VL₁ to VL_(L) and the distributionof electrostatic capacitances between the stylus pen 3 and the K numbersof the horizontal signal lines HL₁ to HL_(K) to the pen positiondetecting unit 18 that is position detecting means. The touchrecognizing unit 17 recognizes the position of a touch on the touchpanel 2 on the basis of the distribution of electrostatic capacitancessupplied from the capacitance distribution calculating unit 16.

The pen position detecting unit 18 detects the position of the styluspen 3 along the horizontal signal lines on the basis of the distributionof electrostatic capacitances between the stylus pen 3 and each of the Lnumbers of the vertical signal lines VL₁ to VL_(L). In addition, the penposition detecting unit 18 detects the position of the stylus pen 3along the vertical signal lines on the basis of the distribution ofelectrostatic capacitances between the stylus pen 3 and each of the Knumbers of the horizontal signal lines HL₁ to HL_(K).

(Detection Operation for Detecting Position of Touch of Touch Pen)

A detection operation for detecting the position of a touch of thestylus pen 3 in the touch panel system 1 having the above configurationwill be described in a temporal manner below. Here, the detectionoperation will be described in a case where the stylus pen 3 is simplyused as a touch pen.

First, in the first signal line drive period, in the first connectionstate where the horizontal signal lines HL₁ to HL_(K) are connected tothe drive lines DL₁ to DL_(K) of the driver 12 and where the verticalsignal lines VL₁ to VL_(L) are connected to the sense lines SL₁ toSL_(L) of the sense amplifier 13, the driver 12 drives the horizontalsignal lines HL₁ to HL_(K) by applying voltage to the drive lines DL₁ toDL_(K).

Then, in the first signal line drive period, charges that areaccumulated in each of the electrostatic capacitances C11 to CKL bydriving the horizontal signal lines HL₁ to HL_(K) and L numbers of firstlinear summation signals that are based on the first pen charge signalwhich is charges corresponding to the electrostatic capacitances betweenthe stylus pen 3 and each of the L numbers of vertical signal lines VL₁to VL_(L) at the time of the approach of the stylus pen 3 to the touchpanel 2 are output from each of the L numbers of the vertical signallines VL₁ to VL_(L).

The sense amplifier 13 reads the L numbers of the first linear summationsignals that include the first pen charge signal through the multiplexer11 and through the sense lines SL₁ to SL_(L) and supplies the L numbersof the first linear summation signals to the AD converter 15. The ADconverter 15 performs AD conversion on the L numbers of the first linearsummation signals that include the first pen charge signal and outputsthe AD-converted L numbers of the first linear summation signals to thecapacitance distribution calculating unit 16.

Next, the first connection state is switched to the second connectionstate so as to change the drive signal and the sense signal of thehorizontal signal lines HL₁ to HL_(K) and the vertical signal lines VL₁to VL_(L). That is, in the second connections state, the horizontalsignal lines HL₁ to HL_(K) are connected to the sense lines SL₁ toSL_(K) of the sense amplifier 13, and the vertical signal lines VL₁ toVL_(L) are connected to the drive lines DL₁ to DL_(L) of the driver 12.

The driver 12, afterward, drives the vertical signal lines VL₁ to VL_(L)by applying voltage to the drive lines DL₁ to DL_(L).

Then, in the second signal line drive period, charges that areaccumulated in each of the electrostatic capacitances C11 to CKL bydriving the vertical signal lines VL₁ to VL_(L) and K numbers of secondlinear summation signals that are based on the second pen charge signalwhich is charges corresponding to the electrostatic capacitances betweenthe stylus pen 3 and each of the K numbers of the horizontal signallines HL₁ to HL_(K) are output from each of the K numbers of thehorizontal signal lines HL₁ to HL_(K). At this time, the sense amplifier13 reads the K numbers of the second linear summation signals thatinclude the second pen charge signal through the multiplexer 11 andthrough the sense lines SL₁ to SL_(K) and supplies the K numbers of thesecond linear summation signals to the AD converter 15. The AD converter15 performs AD conversion on the K numbers of the second linearsummation signals that include the second pen charge signal and outputsthe AD-converted K numbers of the second linear summation signals to thecapacitance distribution calculating unit 16.

Next, in a position detecting process, the capacitance distributioncalculating unit 16 calculates the distribution of electrostaticcapacitances on the touch panel 2 and supplies the first linearsummation signals that include the first pen charge signal, the secondlinear summation signals that include the second pen charge signal, andthe distribution of electrostatic capacitances to the touch recognizingunit 17. The capacitance distribution calculating unit 16 calculates theposition of the stylus pen 3 along the horizontal signal lines and theposition of the stylus pen 3 along the vertical signal lines andsupplies the positions of the stylus pen 3 to the pen position detectingunit 18.

The touch recognizing unit 17, afterward, recognizes the position of atouch on the touch panel 2 on the basis of the distribution ofelectrostatic capacitances supplied from the capacitance distributioncalculating unit 16.

The pen position detecting unit 18 detects the position of the styluspen 3 on the touch panel 2 on the basis of the position of the styluspen 3 along the horizontal signal lines and the position of the styluspen 3 along the vertical signal lines calculated by the capacitancedistribution calculating unit 16.

In the above description, in the present embodiment, both the horizontalsignal lines HL₁ to HL_(K) and the vertical signal lines VL₁ to VL_(L)are driven in a parallel and simultaneous manner. That is, paralleldriving is performed. However, not necessarily limited to this, drivingof the K numbers of the horizontal signal lines HL₁ to HL_(K) anddriving of the L numbers of the vertical signal lines VL₁ to VL_(L) inthe touch panel 2 may be either parallel driving or sequential driving.Parallel driving means that the K numbers of the horizontal signal linesHL₁ to HL_(K) or the L numbers of the vertical signal lines VL₁ toVL_(L) are driven in a parallel and simultaneous manner, and sequentialdriving means that the K numbers of the horizontal signal lines HL₁ toHL_(K) or the L numbers of the vertical signal lines VL₁ to VL_(L) aresequentially driven in order from the horizontal signal line HL₁ or fromthe vertical signal line VL₁. Parallel driving is preferable in terms ofspeed, and the present embodiment uses parallel driving.

As such, the touch panel system 1 of the present embodiment is providedwith the touch panel 2 that has electrostatic capacitances formed ateach intersection of the plurality of first signal lines and theplurality of second signal lines, the touch pen, and the touch panelcontroller 10. The touch panel controller 10, when repeatedly switchingdriving such that the horizontal signal lines HL₁ to HL_(K) that are theplurality of first signal lines are driven to output charge signalsbased on each electrostatic capacitance from each of the vertical signallines VL₁ to VL_(L) that are the second signal lines during the firstsignal line drive period and such that the vertical signal lines VL₁ toVL_(L) that are the plurality of second signal lines are driven tooutput charge signals based on each electrostatic capacitance from eachof the horizontal signal lines HL₁ to HL_(K) that are the first signallines during the second signal line drive period, detects the positionof a touch on the basis of a change in charges of the electrostaticcapacitances due to the touch pen when the touch pen touches the touchpanel 2.

In the touch pen coordinate position detecting method in the touch panelsystem 1 having the above configuration, when the touch pen touches thetouch panel 2, a detected position in the first signal line drive periodand a detected position in the second signal line drive period arerepresented at the same position. Meanwhile, an erroneous signal due tophantom noise that is caused by the touch of a hand, a finger, and thelike of a human body, which receives electromagnetic noise, on the touchpanel 2, even when represented in the first signal line drive period byswitching the first signal lines and the second signal lines, is notrepresented at the same position in the second signal line drive period.Therefore, by determining a detected position with a logical product ofa detected position in the first signal line drive period and a detectedposition in the second signal line drive period, it is possible todistinguish a signal of a touch of the touch pen and an erroneous signaldue to phantom noise and to remove the erroneous signal due to phantomnoise.

Phantom noise is a noise that generates a detection signal based onstatic electricity at a position different from the position of a touchof the touch pen through a hand which holds the touch pen. Since theposition where the detection signal is generated is different from thevalid position of a touch of the touch pen, the detection signal isregarded as noise.

(Configuration of Stylus Pen and Pen Pressure Sensing Function)

The stylus pen 3 of the present embodiment includes a pen pressuresensor that is used to detect a pen pressure level which is aquantitative characteristic value. A configuration of the stylus pen 3will be described on the basis of FIG. 4. FIG. 4 is a sectional viewillustrating a configuration of the stylus pen 3.

The stylus pen 3, as illustrated in FIG. 4, includes a pen main body 30that a user holds with the hand thereof and that includes a conductiveholding portion 30 a which is formed into a substantially cylindricalshape so that the user can hold with the hand thereof. A pen tip portion31 that is pressed to the touch panel 2 at the time of a touch operationis disposed at the tip end of the pen main body 30.

The pen tip portion 31 includes a pen tip cover 31 a, a pen tip axis 31b, insulators 31 c and 31 c that hold the pen tip cover 31 a in a mannercapable of moving the pen tip cover 31 a forward in the axial direction,and a pen pressure sensor 31 d that is disposed on the deep side of thepen tip axis 31 b.

The pen tip cover 31 a is made of insulating material, and the pen tipaxis 31 b is made of conductive material such as metal or conductivesynthetic resin material.

The pen pressure sensor 31 d is configured of, for example, asemiconductor piezoresistive pressure sensor in which a semiconductorstrain gauge is formed on the surface of an unillustrated diaphragm.Therefore, when the pen tip cover 31 a of the pen tip portion 31 ispressed to the touch panel 2 at the time of a touch operation, the pentip axis 31 b is pushed through the pen tip cover 31 a and presses thesurface of the diaphragm of the pen pressure sensor 31 d. Accordingly, achange in electrical resistance due to a piezoresistive effect that isgenerated by the deformation of the diaphragm is converted into anelectrical signal. Accordingly, the pressure of the stylus pen 3 can bedetected. A principle of detecting the pressure of a pen is notnecessarily limited to this. Other principles of detection can be used.

Disposed in the pen main body 30 are a connection switch 32, acontroller circuit 33, operation changing switches 34 a and 34 b, asense circuit 35, the synchronization signal detector circuit 36, atiming adjuster circuit 37, and a drive circuit 38. The connectionswitch 32 may be omitted. When the connection switch 32 is omitted, theoutput of the controller circuit 33 is connected to the pen tip axis 31b.

The connection switch 32 is an electronic switch that is configured of afield-effect transistor (FET) or the like and is controlled in an ON-OFFmanner by the controller circuit 33. When the connection switch 32 isOFF, the pen tip cover 31 a is electrically disconnected from theholding portion 30 a of the pen main body 30. At this time, since thecomponent capacitance of the pen tip portion 31 is very small, the touchpanel system 1 does not recognize approaching or abutting of the styluspen 3 even when the pen tip cover 31 a approaches the touch panel 2.

Meanwhile, when the connection switch 32 is ON, the pen tip cover 31 ais electrically connected to the holding portion 30 a of the pen mainbody 30 through the pen tip axis 31 b, and a human body is conducted tothe pen tip cover 31 a through the holding portion 30 a. Accordingly,since a human body has a comparatively large electrostatic capacitance,when the stylus pen 3 approaches or touches the touch panel 2, chargesaccumulated in each of the electrostatic capacitances C11 to CKL of thetouch panel 2 change, and the touch panel system 1 can detect the stateof the touch of the stylus pen 3.

Disposed in the stylus pen 3 are, for example, a push-type firstoperating switch 39 a and a push-type second operating switch 39 b.Functions assigned to the first operating switch 39 a and the secondoperating switch 39 b are performed through the controller circuit 33 bypushing the first operating switch 39 a and the second operating switch39 b. Examples of a function assigned to the first operating switch 39 acan include an eraser function. The first operating switch 39 a can turnON or OFF the eraser function. In addition, examples of a functionassigned to the second operating switch 39 b can include a mouseright-clicking function. The second operating switch 39 b can turn ON orOFF the mouse right-clicking function.

The eraser function and the mouse right-clicking function are merely anexample. The functions of the first operating switch 39 a and the secondoperating switch 39 b are not limited to the eraser function and themouse right-clicking function. It is also possible to further disposeother operating switches to add other functions.

A signal of a touch of the stylus pen 3 on the touch panel 2, that is,the first pen charge signal and the second pen charge signal indicatingthe position of a touch are detected by switching driving of thehorizontal signal lines HL₁ to HL_(K) and the vertical signal lines VL₁to VL_(L) as described above when the stylus pen 3 touches the touchpanel 2 in a state where the connection switch 32 of the stylus pen 3 isON.

In order to detect a detection signal of the pen pressure of the pen tipportion 31 in the stylus pen 3, the present embodiment uses a methodthat matches the drive pattern of the drive circuit 38 of the stylus pen3 to the drive pattern of the horizontal signal lines HL_(K+1) andHL_(K+2) (or later one) of the touch panel 2 driven by the touch panelcontroller 10, that is, to the drive pattern of the (K+1)-th and(K+2)-th (or later) drive lines DL_(K+1) and DL_(K+2) (or later one) ofthe driver 12 in the first signal line drive period and matches thedrive pattern of the drive circuit 38 to the drive pattern of thevertical signal lines VL_(L+1) and VL_(L+2) (or later one) of the touchpanel 2 driven by the touch panel controller 10, that is, to the drivepattern of the (L+1)-th and (L+2)-th (or later) drive lines DL_(L+1) andDL_(L+2) (or later one) of the driver 12 in the second signal line driveperiod. Here, the horizontal signal lines HL_(K+1) and HL_(K+2) (orlater one) and the vertical signal lines VL_(L+1) and VL_(L+2) (or laterone) do not actually exist. In FIG. 1 and FIG. 2, although drivepatterns may be different depending on the drive periods like the driveline DL_(K+1) and the drive line DL_(L+1) (K≠L), illustration isprovided with a phantom line using the representation of the drive linesDL_(L+1) and DL_(L+2) for convenience of representation. Therepresentation of the drive lines DL_(L+1) and DL_(L+2) will also beused in later descriptions.

Accordingly, in the touch panel controller 10, an increasing ordecreasing signal of the pen pressure sensor 31 d in the stylus pen 3can be obtained through the sense lines SL₁ to SL_(L) by waveforms thatcorrespond to the drive lines DL_(L+1) and DL_(L+2). That is, in thepresent embodiment, by the waveforms that correspond to the drive linesDL_(L+1) and DL_(L+2), an increasing or decreasing signal of the penpressure sensor 31 d in the stylus pen 3 is output, and the signal isdetected by the sense lines SL₁ to SL_(L) through the horizontal signallines HL₁ to HL_(K) or through the vertical signal lines VL₁ to VL_(L)that pass through the position of a touch on the touch panel 2 at thattime.

As a consequence, the controller circuit 33 of the stylus pen 3generates pen pressure information on the basis of the output of the penpressure sensor 31 d, and the pen pressure information is output to thetouch panel controller 10 by the waveforms that correspond to the drivelines DL_(L+1) and DL_(L+2) in response to a transmission instructionfrom the controller circuit 33. A specific method for the output of thepen pressure sensor 31 d will be described later.

(Basic Operation of Synchronization of Touch Panel Controller and StylusPen)

The stylus pen 3 of the present embodiment wirelessly transmits andreceives signals with the touch panel controller 10. Therefore, the pentip portion 31 is driven with the same pattern as driving the drive lineDL_(L+1) or DL_(L+2) in accordance with the timing of driving the drivelines DL₁ to DL_(L) in the touch panel controller 10. Therefore, thedrive circuit 38 is disposed in the stylus pen 3 so that the stylus pen3 can be driven in the same manner as the driver 12 of the touch panelcontroller 10.

Driving of the drive lines DL₁ to DL_(L) in the touch panel controller10 is based on a drive timing that is generated by the timing generator14. Thus, the stylus pen 3 has to operate in synchronization with thetiming when the touch panel controller 10 is driven. Therefore, bydisposing the sense circuit 35, the synchronization signal detectorcircuit 36, and the timing adjuster circuit 37 in the stylus pen 3 ofthe present embodiment, the dedicated synchronization signal that thetouch panel controller 10 drives is detected in the stylus pen 3, andthe timing of the dedicated synchronization signal of the touch panelcontroller 10 is matched to the timing of a pen synchronization signalthat is generated by the timing adjuster circuit 37 of the stylus pen 3.

A basic principle of the synchronization of the stylus pen 3 in thetouch panel system 1 will be described on the basis of FIG. 5. FIG. 5 isa timing chart illustrating the basic principle of synchronization.

The stylus pen 3 detects the dedicated synchronization signal generatedby the timing generator 14 of the touch panel controller 10 with thesense circuit 35 and the synchronization signal detector circuit 36. Thededicated synchronization signal is assumed to be a single pulse forsimplification.

As illustrated in FIG. 5, it is assumed that a touch panelsynchronization signal S0 that is the dedicated synchronization signalconfigured of a single pulse is generated in a constant cycle.

The sense circuit 35 of the stylus pen 3 generates a plurality ofsynchronization signal candidates S1 to Sp (p is an integer greater thanor equal to two). The synchronization signal candidate Sp illustrated inFIG. 5 represents a signal that is delayed by approximately one cyclefrom the synchronization signal candidate S1. The stylus pen 3 selects asynchronization signal that has a high degree of matching with thededicated synchronization signal transmitted from the timing generator14 of the touch panel controller 10 from the synchronization signalcandidates S1 to Sp and uses the synchronization signal as asynchronization signal for communication with the touch panel controller10. In the example illustrated in FIG. 5, the synchronization signalcandidate S4 or S5 that has a high degree of matching with the touchpanel synchronization signal S0 is used as the pen synchronizationsignal of the stylus pen 3.

The stylus pen 3 is in a detection mode until being synchronized, andthe drive circuit 38 is not driven.

According to such a principle, the stylus pen 3 can synchronize with thededicated synchronization signal of the touch panel controller 10.

(Synchronization Operation of Touch Panel Controller and Stylus Pen ofPresent Embodiment)

In actuality, synchronization is not easy because noise exists in thereception of the dedicated synchronization signal from the touch panelcontroller 10. Specifically, since a low-frequency component issuperimposed on the dedicated synchronization signal, it is difficult tocorrectly obtain the amplitude of the pulse of the dedicatedsynchronization signal. As a consequence, a problem arises in that thepulse of the dedicated synchronization signal may not be captured.

An example of a method for resolving such a problem will be described onthe basis of FIG. 6(a) to FIG. 12(c). FIG. 6(a) is a diagramillustrating an output relationship between the drive line of the driverand the sense line of the sense amplifier in the touch panel controllerto the touch panel and the stylus pen, and FIG. 6(b) is a waveformdiagram illustrating a synchronization waveform and a touch detectionwaveform. FIG. 7(a) is a waveform diagram illustrating a drive waveform,such as a synchronization waveform and a touch detection waveformtransmitted from the touch panel controller to the stylus pen, and alow-frequency noise, FIG. 7(b) is a waveform diagram illustrating astate where the drive waveform and the low-frequency noise aresuperimposed, and FIG. 7(c) is a waveform diagram illustrating a statewhere the superimposed waveform is reset at reset timings. FIG. 8 is adiagram illustrating a configuration of a reset circuit disposed in thesynchronization signal detector circuit of the stylus pen. FIG. 9(a) isa waveform diagram illustrating an example of a synchronization waveformtransmitted from the touch panel controller, FIG. 9(b) is a waveformdiagram illustrating an input waveform received by the stylus pen, FIG.9(c) is a waveform diagram illustrating an internal waveform when areference potential is set at a reset timing R1 in FIG. 9(b), and FIG.9(d) is a waveform diagram illustrating an internal waveform when areference potential is set at a reset timing R2 in FIG. 9(b). FIG. 10(a)is a waveform diagram illustrating a synchronization waveform that usesthe M-sequence code “1110010” which is not Manchester-coded, and FIG.10(b) is a waveform diagram illustrating a synchronization waveform thatuses the Manchester-coded M-sequence code “1110010”. FIG. 11(a) is awaveform diagram illustrating an example of a synchronization waveformthat has a long High period and is transmitted from the touch panelcontroller, FIG. 11(b) is a waveform diagram illustrating a reset timingR3 of an input waveform received by the stylus pen, and FIG. 11(c) is awaveform diagram illustrating an internal waveform when a referencepotential is set at the reset timing R3 in FIG. 11(b). FIG. 12(a) is adiagram illustrating a synchronization waveform of a pseudorandomsequence that has periodicity, is Manchester-coded, and is transmittedto the stylus pen from the touch panel controller of the touch panelsystem, and FIG. 12(b) is a waveform diagram illustrating thesynchronization waveform and a touch detection waveform.

In the touch panel system 1 of the present embodiment, as illustrated inFIG. 6(a), the dedicated synchronization signal of the touch panelcontroller 10 is created in the timing generator 14 of the touch panelcontroller 10 and is transmitted by the driver 12 using the drive linesDL₁ to DL_(L). As a mechanism that notifies the stylus pen 3 of thededicated synchronization signal which is the drive timing of the touchpanel controller 10, as illustrated in FIG. 6(b), the drive lines DL₁ toDL_(L) are driven by a waveform that represents synchronizationseparately from a normal touch detection waveform. Specifically, thetouch detection waveform is generated after the synchronization waveformis generated in each of the drive lines DL₁ to DL_(L). For easyunderstanding of description, the touch detection waveform is generatedby sequential driving. In addition, representing the generation of thesynchronization waveform with a plurality of continuous pulses is tofacilitate distinguishing the appearance of the synchronization waveformfrom the waveform of sequential driving. In actuality, a waveformobtained by Manchester-coding the M-sequence code suggested in thepresent embodiment or the like is more likely to be detected as asynchronization waveform.

Various types of noise, particularly low-frequency noise, are mixed intothe waveform of a signal received by the stylus pen 3. In FIG. 7(a), itis assumed that a wide straight line illustrates the dedicatedsynchronization waveform that is configured of a plurality of densepulses which the touch panel controller 10 drives and that a sin curveillustrates noise.

The waveform of the signal received by the stylus pen 3 is configured ofthe superimposition of the synchronization waveform obtained from thetouch panel controller 10 and low-frequency noise as illustrated in FIG.7(b). As a consequence, in the waveform of the signal received by thestylus pen 3, the amplitude of low-frequency noise is larger than theamplitude of the synchronization waveform obtained from the touch panelcontroller 10. Thus, when using the waveform of the received signal fromthe minimum potential to the maximum potential thereof, it is difficultto obtain the synchronization waveform signal because the amplitude ofthe synchronization waveform signal is a relatively minute amplitude incomparison with the noise.

Therefore, as a method for finding the synchronization waveform from thewaveform illustrated in FIG. 7(b) in which the synchronization waveformand low-frequency noise are superimposed, for example, there are amethod of removing low-frequency noise with a low frequency cut-offfilter and a method of performing a reset operation that sets areference potential for the waveform in which the synchronizationwaveform and low-frequency noise are superimposed and obtaining theamplitude of an internal waveform by using the potential difference fromthe reference potential. However, low frequency cut-off filters areexpensive.

In the present embodiment, thus, the stylus pen 3 that is on thereception side of the synchronization waveform uses the method ofperforming a reset operation that sets a reference potential for thereceived input waveform and obtaining the amplitude of an internalwaveform by using the potential difference from the reference potential.However, the present invention is not necessarily limited to this. It isalso possible to remove noise that is configured of low-frequencycomponents by using a low frequency cut-off filter.

In the present embodiment, the synchronization signal detector circuit36 of the stylus pen 3 is provided with a reset circuit 36 a illustratedin FIG. 8 so as to perform a reset operation that sets a referencepotential for the received input waveform. The reset circuit 36 a resetsthe superimposed signal waveform illustrated in FIG. 7(b) in which thesynchronization waveform obtained from the touch panel controller 10 andlow-frequency noise are superimposed. By resetting the superimposedsignal waveform, the superimposed signal waveform returns to thereference potential at a reset timing as illustrated in FIG. 7(c). Thatis, the reference potential is set to the same potential as the inputsignal. Then, a positive potential is output when the potential of thesuperimposed signal waveform input is higher than the referencepotential, while a negative potential is output when the potential ofthe superimposed signal waveform input is lower than the referencepotential. Accordingly, it is possible to remove low-frequencycomponents and to keep the amplitude of the signal within a certainrange.

When a reset operation that sets a reference potential for the receivedinput waveform is performed on the synchronization waveform that isobtained from the touch panel controller 10 and that is represented by asequence of a plurality of equidistant pulses, a problem arises in thatit is difficult to identify the dedicated synchronization signal that isthe drive timing of the touch panel controller 10 because pulses are notcaptured when the reset timing that sets a reference potential for thereception-side stylus pen 3 overlaps with the pulses of thesynchronization waveform.

When, for example, the synchronization waveform illustrated in FIG. 9(a)is transmitted from the touch panel controller 10, an input waveform inthe reception-side stylus pen 3 is illustrated by the waveform of FIG.9(b). At this time, the internal waveform when the reference potentialis set at the reset timing R1 in the waveform of FIG. 9(b) isillustrated in FIG. 9(c). However, when the reset timing R2 is set tothe second pulse in the waveform of FIG. 9(b), the internal waveformwhen the reference potential is set is as illustrated in FIG. 9(d). As aconsequence, since the second pulse does not have a positive rise, thesecond pulse is not captured. That is, it is difficult to identify thededicated synchronization signal that is the drive timing of the touchpanel controller 10.

The present embodiment, therefore, uses a constant patternsynchronization signal that is configured of a pseudorandom sequencehaving periodicity as a synchronization waveform that is transmitted bythe touch panel controller 10. Specifically, an M-sequence code or aGold sequence code is used.

The pseudorandom sequence is a code sequence that is used in apseudorandom signal which is an artificially created random signal. Thatis, while actual random signals existing in nature are usually called arandom signal, artificially created random signals are called apseudorandom signal. Although a certain rule is necessary since thepseudorandom signal is artificially created, various considerations aremade to make the statistical properties of the created signal as closeas possible to the statistical properties of the actual random signal.Usually, considerations are made to make the autocorrelation function ofthe created signal as close as possible to the autocorrelation functionδ(t) of white noise. The pseudorandom signal is created by associating apseudorandom sequence (a sequence of numbers) with physical quantitiessuch as voltage. Types of pseudorandom sequences include a finite lengthsequence and a periodic sequence. Periodic sequences are widely used interms of ease of generation and usage. There are an M-sequence and aGold sequence that represent the periodic sequence.

The autocorrelation of an M-sequence signal and a Gold sequence codeshows a very sharp peak and has properties such that the correlationvalues with others except for the M-sequence signal and the Goldsequence code are very small. The M-sequence and the Gold sequence aresequences that are configured of binary numbers of zero and one and thathave periodicity in which binary sequences are connected.

The reliability of determining synchronization is increased by using theM-sequence code or Gold sequence code as a synchronization waveformtransmitted by the touch panel controller 10 even when the reset timingoverlaps with one pulse because pulses that match the M-sequence codeare determined as a correct synchronization timing.

When, for example, the M-sequence code “1110010” is used as illustratedin FIG. 10(a), the synchronization waveform illustrated in FIG. 10(a)can be obtained by associating “0” with Low of the synchronizationwaveform and associating “1” with High of the synchronization waveform.

As described above, tolerance to pulses not being captured is increasedby using the M-sequence code as a synchronization waveform transmittedby the touch panel controller 10 and by determining whether pulses matchthe same M-sequence code in the sense circuit 35 and the synchronizationsignal detector circuit 36 of the stylus pen 3. However, when thesequence is long, the sequence includes a pattern in which the number ofcontinuous Highs or Lows is large. Thus, when the reset timing that setsa reference potential is set in this part, an unnecessary potentialchange occurs to make the determination of a waveform difficult.

For example, an internal waveform when there are High pulses in a longperiod in the synchronization waveform transmitted by the touch panelcontroller 10 as illustrated in FIG. 11(a) and when a referencepotential is set at the reset timing R3 in the input waveform receivedby the stylus pen 3 illustrated in FIG. 11(b) becomes as illustrated inFIG. 11(c), and it is difficult to detect the internal waveform.

Therefore, the present embodiment uses a waveform that is obtained byManchester-coding a code having good autocorrelation characteristicssuch as the M-sequence, and the waveform is driven as thesynchronization waveform of the touch panel controller 10. TheManchester-coded waveform means associating “0” with High→Low of thesynchronization waveform and associating “1” with Low→High of thesynchronization waveform as illustrated in FIG. 10(b). The opposite mayalso be possible. Accordingly, as illustrated in FIG. 10(b), it ispossible to prevent the occurrence of a case where the period of High orLow is long when the M-sequence code “1110010” is used.

As such, considering the reset operation, it is preferable that theManchester-coded M-sequence code or Gold sequence code is used.

In the present embodiment, as illustrated in FIG. 12(a), for example,the above 7-bit M-sequence code “1110010” that is Manchester-coded isused to associate pulses as illustrated in FIG. 12(a). Then, the pulsesare used as a synchronization waveform of the touch panel controller 10as illustrated in FIG. 12(b).

Accordingly, a period of long continuous Highs or Lows does not appearin the synchronization waveform, and it is possible to use asynchronization pattern of which the autocorrelation characteristicsfacilitate the detection of the synchronization pattern. In addition,since High or Low is continuous at most during a time that representsone bit in the synchronization waveform, it is also possible to adjustthe reset timing that sets a reference potential by the reception-sidestylus pen 3.

For example, when a state where potential is high continues for the timethat represents one bit or longer, this is regarded as the influence ofnoise, and the potential at that point in time is set for a laterreference potential. In addition, when the state changes from the highpotential close to the reference potential, the potential at that pointin time is set for a later reference potential. Accordingly, even whenpotential significantly decreases due to noise and the like, it ispossible to track the potential.

(Continuous Operation of Synchronization of Touch Panel System andStylus Pen and Touch Position Detection)

Continuous operation of the synchronization of the touch panel system 1and the stylus pen 3 having the above configurations and touch positiondetection will be described on the basis of FIG. 13 and FIGS. 14(a) to14(c). FIG. 13 is an operation image diagram illustrating acorrespondence between a drive operation of the touch panel controller10 and a drive operation of the stylus pen 3. FIGS. 14(a) to 14(c) arediagrams illustrating a specific drive operation in a synchronizationsignal detection period, a pause period, and a normal drive periodillustrated in FIG. 13.

The drive operation of the stylus pen 3, as illustrated in FIG. 13, isconfigured by repeating three periods of a synchronization signaldetection period that is set for detecting the synchronization signalfrom the touch panel controller 10 with the sense circuit 35 and thesynchronization signal detector circuit 36 by turning the operationchanging switch 34 a ON and by turning the operation changing switch 34b OFF, a preparation period, and a drive mode period during which thedrive circuit 38 drives the pen tip portion 31 by turning the operationchanging switch 34 a OFF and by turning the operation changing switch 34b ON.

The synchronization signal detection period is a standby period fordetecting a bit pattern that represents the synchronization waveform andis a period during which the synchronization signal pattern is detectedfrom a pen tip signal waveform while the pen tip portion 31 is notdriven. Specifically, in the synchronization signal detection period, asillustrated in FIG. 14(a), each of the drive lines DL₁ to DL_(L) of thedriver 12 is driven with the same waveform. The pattern of the waveformused includes a pattern that has autocorrelation characteristics such asthe M-sequence.

The preparation period illustrated in FIG. 13 is a preparation periodfor selecting a code to drive on the basis of additional informationafter the detection of the synchronization signal pattern and on thebasis of the state of the stylus pen 3 and for starting to drive the pentip in accordance with the timing of the touch panel controller 10 andis a period during which the additional information that includes thetiming of starting driving is interpreted.

The drive mode period is a period during which the pen tip portion 31 isdriven by the drive circuit 38 and is a period during which the pen tipportion 31 is driven with the selected code while the edge of the drivewaveform is finely adjusted in accordance with the drive timing of thetouch panel controller 10. At this time, the drive circuit 38 of thestylus pen 3 is driven in accordance with the drive timing of the touchpanel controller 10.

Meanwhile, the drive operation of the touch panel controller 10 isconfigured by repeating three periods of a period during which the drivelines DL₁ to DL_(L) are driven with the same waveform, a pause period,and a period during which driving of the drive lines DL₁ to DL_(K) anddriving of the sense lines SL₁ to SL_(K) to SL_(L) are switched.

The period during which the drive lines DL₁ to DL_(L) are driven withthe same waveform is a period during which the additionalinformation+the synchronization waveform for the synchronization of thestylus pen 3 are driven. Specifically, as illustrated in FIG. 14(b), thedrive lines DL₁ to DL_(L) are driven with the same waveform.

The pause period is a period during which the stylus pen 3 ends thedetection of synchronization and prepares for driving. Specifically, asillustrated in FIG. 14(b), the pause period is a standby period fordisposing a preparation period during which the stylus pen 3 detects thesynchronization waveform and performs normal driving. Thus, the drivewaveform during the pause period does not have any meaning and iscompletely arbitrary. Therefore, driving may not be performed in thepause period. This duration is not necessary when the preparation periodon the stylus pen 3 side is not necessary.

Next, the period during which driving of the drive lines DL₁ to DL_(K)to DL_(L) and driving of the sense lines SL₁ to SL_(K) to SL_(L) areswitched is a normal drive period for position detection that isperformed to obtain data of one face of the touch panel 2. Specifically,in the normal drive period, as illustrated in FIG. 14(c), driving of thedrive lines DL₁ to DL_(K) to DL_(L) with a waveform necessary fordetecting the position of a touch of the stylus pen 3 and sensing arerepeated. Methods for driving include sequential driving and paralleldriving. In FIG. 14(c), sequential driving is represented so as tofacilitate visual understanding of the order of drive patterns.

The stylus pen 3, when detecting the synchronization waveform, drivesthe pen tip portion 31 with the same waveform as the drive linesDL_(L+1) and DL_(L+2) that correspond to the outside of the touch panel2. In FIG. 14(c), colored backgrounds indicate a sense period, that is,a period during which a charge signal of an electrostatic capacitancefor detecting the position of a touch is detected.

(Output Operation of Stylus Pen Outputting Quantitative CharacteristicValue Such as Pen Pressure Level)

A mechanism of outputting a quantitative characteristic value such as apen pressure level in the stylus pen 3 of the present embodiment will bedescribed on the basis of FIG. 1, FIG. 15, and FIG. 16. FIG. 15 is adiagram illustrating a relationship between a drive pattern of thedriver in the touch panel controller and a drive pattern of the drivecircuit in the stylus pen. FIG. 16 is a diagram illustrating a penpressure value that is obtained in the stylus pen and a pen pressurevalue that is represented in the stylus pen having the pen pressure andin the touch panel controller.

As described above, the stylus pen 3 of the present embodiment isprovided with the pen pressure sensor 31 d and is configured of anelectronic pen that outputs a quantitative characteristic value such asa pen pressure level. Thus, in order to transmit a quantitativecharacteristic value that is detected by the stylus pen 3 to the touchpanel controller 10 side, the transmission has to use many types ofidentifiable signals because there are many types of information. As aconsequence, a problem arises in that the amount of signals increases,requiring more time for transmission, and the identification of thesignal on the reception side becomes complicated.

In the present embodiment, therefore, as illustrated in FIG. 1 and FIG.15, the stylus pen 3 is configured of an electronic pen that outputs aquantitative characteristic value, and the stylus pen 3 produces anoutput that indicates that the quantitative characteristic value in thestylus pen 3 is increased from the characteristic value of the previousoutput by using a waveform that corresponds to the drive line DL_(L+1)as the (L+1)-th drive signal line. Meanwhile, the stylus pen 3 producesan output that indicates that the quantitative characteristic value inthe stylus pen 3 is decreased from the characteristic value which isupdated and retained in the previous output by using a waveform thatcorresponds to the drive line DL_(L+2) as the (L+2)-th drive signalline. Furthermore, in order to determine a next increase or decrease,the result of the current output of an increase or decrease is reflectedon the characteristic value that is retained internally. The touch panelcontroller 10 is provided with a conversion output unit 19 that convertsand outputs a quantitative characteristic value by using the sum of theinitial value of the quantitative characteristic value and the number ofoutputs×the unit amount of increase or decrease in the waveform thatcorresponds to the (L+1)-th drive line DL_(L+1) or in the waveform thatcorresponds to the (L+2)-th drive line DL_(L+2).

Specifically, as illustrated in FIG. 15, when the stylus pen 3 detectspen pressure with the pen pressure sensor 31 d and when the pen pressurevalue of the pen pressure sensor 31 d is increased from the value of theprevious output, the stylus pen 3 drives the pen tip portion 31 with thewaveform that corresponds to the drive line DL_(L+1) while the driver 12of the touch panel controller 10 drives the drive lines DL₁ to DL_(L).Alternatively, when the stylus pen 3 detects pen pressure with the penpressure sensor 31 d and when the pen pressure value of the pen pressuresensor 31 d is decreased from the value of the previous output, thestylus pen 3 drives the pen tip portion 31 with the waveform thatcorresponds to the drive line DL_(L+2) while the driver 12 of the touchpanel controller 10 drives the drive lines DL₁ to DL_(L).

Accordingly, by the waveforms that correspond to the drive linesDL_(L+1) and DL_(L+2), an increasing or decreasing signal of the penpressure sensor 31 d in the stylus pen 3 is output, and the signal isdetected by the sense lines SL₁ to SL_(L) through the horizontal signallines HL₁ to HL_(K) or through the vertical signal lines VL₁ to VL_(L)that pass through the position of a touch on the touch panel 2 at thattime.

When the pen pressure value is not transmitted from the stylus pen 3yet, the value of the previous output, that is, the characteristic valuethat is retained internally is set to “0”. For example, at the start ofa touch, the previously transmitted value, that is, the characteristicvalue that is retained internally is “0”.

An interval during which a pen pressure increase or decrease signal ofthe pen pressure sensor 31 d is transmitted from the stylus pen 3 occursonce in a drive period during which the driver 12 drives the drive linesDL₁ to DL_(L) once. While driving performed by sequential driving isillustrated in FIG. 15 for easy understanding, driving may be performedby parallel driving.

That is, in the present embodiment, the stylus pen 3 transmits only twotypes of information that indicates whether the quantitativecharacteristic value is increased or decreased from the characteristicvalue of the previous output. However, by using the two types ofinformation, it is possible to obtain whether the pen pressure value ofthe pen pressure sensor 31 d is increased or decreased on the touchpanel controller 10 side.

As illustrated in FIG. 1, the conversion output unit 19 is disposed inthe touch panel controller 10. A summation unit 19 a of the conversionoutput unit 19 is configured to convert and output the quantitativecharacteristic value by using the sum of the initial value of thequantitative characteristic value and the number of outputs×the unitamount of increase or decrease in the waveform that corresponds to the(L+1)-th drive line DL_(L+1) or in the waveform that corresponds to the(L+2)-th drive line DL_(L+2). A positive value is used for the unitamount of increase or decrease when counting the output of the waveformthat corresponds to the (L+1)-th drive line DL_(L+1). Meanwhile, anegative value is used for the unit amount of increase or decrease whencounting the output of the waveform that corresponds to the (L+2)-thdrive line DL_(L+2).

Accordingly, even when a quantitative characteristic value that has manytypes of information is output, only two types of signals related toincrease and decrease are used. Thus, the amount of signals is small,and transmission can be performed in a short amount of time. Forexample, when the characteristic value is obtained in 10 bits, more timeis required because transmission is performed in any form ten times morethan one-bit information of increase or decrease. Signal processing inthe conversion output unit 19 of the reception-side touch panelcontroller 10 is simplified because it is only necessary to obtain thecumulative value of increase and decrease from the initial value of thequantitative characteristic value.

As a consequence, for example, the pen pressure value illustrated inFIG. 16 can be obtained. The pen pressure value data illustrated in FIG.16 starts with an initial value of “0”. It is assumed that the penpressure value has a value in the range of 0 to 1.0 and that the actualpen pressure value obtained in the pen tip portion 31 of the stylus pen3 is illustrated by a curve in FIG. 16.

As an internal process of the stylus pen 3 performed on the curve, thepen pressure is represented by a value that changes by 0.2. Thisinternal process is performed by the controller circuit 33 of the styluspen 3. In the controller circuit 33, a determination of whether theinternal pen pressure value has to be increased or decreased to approachthe pen pressure value of the curve is performed, and the internal penpressure value is updated on the basis of the determination. Theincrease or decrease is represented as a drive waveform of the pen tipportion 31.

On the touch panel controller 10 side that receives the increase ordecrease information, a pen pressure value change that is the same asthe internal pen pressure value of the stylus pen 3 can be reproduced bythe sum of the initial value “0” as a reference and the number ofoutputs×the unit amount of increase or decrease “0.2” obtained by theconversion output unit 19.

Therefore, when the stylus pen 3 that outputs a quantitativecharacteristic value such as pen pressure data which has many types ofinformation is used, it is possible to provide the touch panel system 1that may transmit the information simply in a short amount of time.

As such, in the touch panel system 1 of the present embodiment, sincethe driver 12 as a synchronization signal transmission unit of the touchpanel controller 10 transmits the synchronization signal to the styluspen 3 during synchronization signal transmission periods immediatelybefore each of the first signal line drive period and the second signalline drive period, it is possible to create the synchronization signalby using a drive signal for driving the first signal lines and thesecond signal lines. Thus, a separate circuit for creating thesynchronization signal is not disposed, and the number of components canbe reduced. Regarding a typical touch detection drive pattern, theM-sequence may be used in parallel driving. When the M-sequence is alsoused for the synchronization signal, it is not necessary to dispose aseparate circuit. However, a separate circuit is required in sequentialdriving because it is necessary to generate the synchronization signal.A separate circuit is also required even in parallel driving whendriving is performed by using a Hadamard matrix that has orthogonalitysince the Hadamard matrix is different from the M-sequence of thesynchronization signal.

When the synchronization signal is wirelessly transmitted from the touchpanel controller 10 to the stylus pen 3, low-frequency signals aresuperimposed as noise on the synchronization signal. Thus, thesynchronization signal may not be captured when noise is notappropriately separated in the case of a single pulse. Meanwhile, in thecase of a plurality of unchanging pulses that has the same pitch, it isunclear which part corresponds to the synchronization signal.

Therefore, in the present embodiment, the driver 12 of the touch panelcontroller 10 transmits a synchronization signal having a waveform thatis configured of a pseudorandom sequence having periodicity such as theM-sequence code or the Gold sequence code to the stylus pen 3 during thesynchronization signal transmission period, and the stylus pen 3 isprovided with the sense circuit 35 and the synchronization signaldetector circuit 36 as a synchronization signal detecting unit thatdetects the synchronization signal.

Thus, the synchronization signal, since being transmitted with awaveform that is configured of a pseudorandom sequence havingperiodicity, has good autocorrelation characteristics. Thus, accuracyincreases in identifying the synchronization signal, and it is possibleto reduce the synchronization signal not being captured.

Therefore, it is possible to provide the touch panel system 1 that canappropriately detect the synchronization signal.

When the synchronization signal on which low-frequency components aresuperimposed is received and when the reset operation is performed withpulses having a long High period or Low period in the case of detectingthe amplitude of the synchronization signal by periodically performingthe reset operation to return the received input waveform to thereference potential, potential changes unnecessarily, and it isdifficult to determine the waveform.

Therefore, in the present embodiment, the synchronization signal havinga waveform configured of a pseudorandom sequence is Manchester-coded.That is, in the Manchester-coding process, a process of associating “0”of the pseudorandom sequence with High→Low of the synchronizationwaveform and associating “1” with Low→High of the synchronizationwaveform is performed. The opposite may also be possible. Accordingly,it is possible to prevent the period of High or Low from beinglengthened.

In the touch panel system 1 of the present embodiment, the driver 12 asa synchronization signal transmission unit of the touch panel controller10 doubles as the driver 12 as a drive unit that supplies a drive signalfor driving the horizontal signal lines HL₁ to HL_(K) as the pluralityof first signal lines or the vertical signal lines VL₁ to VL_(L) as theplurality of second signal lines. The driver 12 transmits thesynchronization signal by changing the drive signal for driving theplurality of horizontal signal lines HL₁ to HL_(K) or the plurality ofvertical signal lines VL₁ to VL_(L) to a waveform that is configured ofa Manchester-coded pseudorandom sequence having periodicity.

Accordingly, since the synchronization signal transmission unit isconfigured of the driver 12 that doubles as a drive unit, it is possibleto create the synchronization signal by simply changing the waveformpattern of the drive signals of the drive lines DL₁ to DL_(L) that areused to drive the horizontal signal lines HL₁ to HL_(K) and the verticalsignal lines VL₁ to VL_(L). Thus, a separate circuit for creating thesynchronization signal is not disposed, and the number of components canbe certainly reduced. As described above, this result is limited to thecase where the M-sequence is also used for the synchronization signal inparallel driving.

The touch panel system 1 of the present embodiment is provided with thestylus pen 3 as a touch pen, the touch panel 2, and the touch panelcontroller 10. The touch panel 2 has electrostatic capacitances formedat each intersection of the horizontal signal lines HL₁ to HL_(K) as theK (K is an integer greater than or equal to two) numbers of the firstsignal lines and the vertical signal lines VL₁ to VL_(L) as the L (L isan integer satisfying L≧K) numbers of the second signal lines. The touchpanel controller 10 outputs drive signals that drive the K numbers ofthe horizontal signal lines HL₁ to HL_(K) or the L numbers of thevertical signal lines VL₁ to VL_(L) from the driver 12 as a drive unitthrough the drive lines DL₁ to DL_(L) as the L numbers of drive signallines and receives input of detection signals from the K numbers of thehorizontal signal lines HL₁ to HL_(K) or the L numbers of the verticalsignal lines VL₁ to VL_(L) detected by the sense amplifier 13 as adetecting unit through the sense lines SL₁ to SL_(L) as the L numbers ofdetection signal lines on the basis of a change in charges accumulatedin the electrostatic capacitances due to the stylus pen 3 when thestylus pen 3 touches the touch panel 2.

The stylus pen 3 is configured of an electronic pen that outputs aquantitative characteristic value, and the stylus pen 3 produces anoutput that indicates that the quantitative characteristic value in thestylus pen 3 is increased from the characteristic value of the previousoutput by using the waveform that corresponds to the (L+1)-th drive lineDL_(L+1) and, meanwhile, produces an output that indicates that thequantitative characteristic value in the stylus pen 3 is decreased fromthe characteristic value of the previous output by using a waveform thatcorresponds to the (L+2)-th drive line DL_(L+2). The touch panelcontroller 10 is provided with the conversion output unit 19 thatconverts and outputs a quantitative characteristic value by using thesum of the initial value of the quantitative characteristic value andthe number of outputs×the unit amount of increase or decrease in thewaveform that corresponds to the (L+1)-th drive line DL_(L+1) or in thewaveform that corresponds to the (L+2)-th drive line DL_(L+2).

Accordingly, since only two types of signals related to increase anddecrease are used even when a quantitative characteristic value that hasmany types of information is output, the amount of signals is small, andtransmission can be performed in a short amount of time. In addition,signal processing on the reception side is simplified because it is onlynecessary to obtain the cumulative value of increase and decrease fromthe initial value of the quantitative characteristic value.

Therefore, when the stylus pen 3 that outputs a quantitativecharacteristic value which has many types of information is used, it ispossible to provide the touch panel system 1 that may transmit theinformation simply in a short amount of time.

In the touch panel system 1 of the present embodiment, the stylus pen 3as an electronic pen is provided with the pen pressure sensor 31 d.Accordingly, it is possible to detect a pen pressure level that is aquantitative characteristic value when the stylus pen 3 touches thetouch panel 2.

The present invention is not limited to the above embodiment. Variousmodifications can be carried out within the scope of the presentinvention. For example, while the pen pressure level of the pen pressuresensor 31 d is used as an example of a quantitative characteristic valuein the embodiment, the present invention is not particularly limited tothis.

As an example of a quantitative characteristic value, for example, ashade level can also be used as a quantitative characteristic valuewhen, for example, a colored character is displayed by the stylus pen 3.

Second Embodiment

Another embodiment of the present invention will be described as followson the basis of FIG. 17 to FIG. 20. Configurations other than thosedescribed in the present embodiment are the same as those of the firstembodiment. For convenience of description, members having the samefunction as the members illustrated in the drawings of the firstembodiment will be designated by the same reference sign, anddescriptions thereof will be omitted.

The touch panel system 1 of the present embodiment is different in thatthe conversion output unit 19 of the touch panel controller 10 canchange the unit amount of increase or decrease.

A configuration of the touch panel system 1 of the present embodimentwill be described on the basis of FIG. 17. FIG. 17 is a block diagramillustrating the configuration of the touch panel system 1 of thepresent embodiment.

In the touch panel system 1 of the present embodiment, as illustrated inFIG. 17, a unit increase or decrease amount changing unit 19 b thatchanges the unit amount of increase or decrease is disposed in theconversion output unit 19.

When, for example, the quantitative characteristic value of the styluspen 3 is generated in a short amount of time, a difference occursbetween the quantitative characteristic value and the actualquantitative characteristic value of the stylus pen 3 if the unit amountof increase or decrease is not increased.

In the present embodiment, therefore, the unit increase or decreaseamount changing unit 19 b is disposed in the conversion output unit 19,and the unit amount of increase or decrease is changed by the unitincrease or decrease amount changing unit 19 b. Accordingly, it ispossible to suppress the occurrence of a difference between thequantitative characteristic value and the actual quantitativecharacteristic value of the stylus pen 3.

What can be detected by the conversion output unit 19 is only the numberof outputs in a certain amount of time in the waveform that correspondsto the (L+1)-th drive line DL_(L+1) or in the waveform that correspondsto the (L+2)-th drive line DL_(L+2). Therefore, the problem is how theunit increase or decrease amount changing unit 19 b determines whetherto change the unit amount of increase or decrease.

In the present embodiment, therefore, as illustrated in FIG. 17, acontinuous increase or decrease changing unit 19 c is disposed in theunit increase or decrease amount changing unit 19 b. The continuousincrease or decrease changing unit 19 c is configured to increase ordecrease the unit amount of increase or decrease from the previous valuewhen the number of continuous outputs in each of the waveform thatcorresponds to the (L+1)-th drive line DL_(L+1) and the waveform thatcorresponds to the (L+2)-th drive line DL_(L+2) is P (P is an integergreater than or equal to two).

That is, for example, when the number of continuous outputs in thewaveform that corresponds to the (L+1)-th drive line DL_(L+1) is P (P isan integer greater than or equal to two), it is determined that a rapidchange occurs, and the unit amount of increase or decrease is, forexample, doubled. When increase further continues, the unit amount ofincrease or decrease is further increased.

Specifically, for example, as illustrated in FIG. 18, when the internalpen pressure value of the stylus pen 3 is represented by changing theunit amount of increase or decrease by 0.1, there may be a case wherethe internal pen pressure value cannot sufficiently keep up with thespeed of change even in the case of the same amount of a pen pressurechange.

In the present embodiment, therefore, as illustrated in FIG. 19, theunit amount of increase or decrease is increased from 0.1 to 0.2 whenthe pen pressure value is continuously increased or decreased twice.When the pen pressure value is further increased or decreased once more,the unit amount of increase or decrease is further increased to 0.3.

Meanwhile, when increase or decrease does not continue, the unit amountof increase or decrease is decreased. When increase and decrease arecontinuously repeated, the unit amount of increase or decrease isfurther decreased. As such, for example, the next unit amount ofincrease or decrease is increased when increase or decrease continuestwice, or otherwise, the next unit amount of increase or decrease isdecreased.

The unit amount of increase or decrease is increased or decreased by0.1. However, the range of increase or decrease of the unit amount ofincrease or decrease is greater than or equal to 0.1 and less than orequal to 0.3.

While the pen pressure value is reproduced by disposing the unitincrease or decrease amount changing unit 19 b in the touch panelcontroller 10 in the present embodiment, it is also possible that thepen pressure is transmitted to the touch panel controller 10 side bydisposing the unit increase or decrease amount changing unit 19 b andthe continuous increase or decrease changing unit 19 c on the stylus pen3 side. Accordingly, in the conversion output unit 19 of the touch panelcontroller 10, if an increase or decrease in the pen pressure value isobtained, the unit amount of increase or decrease can be set to the samestate as the range of change in the stylus pen 3 by finding how manytimes an increase or decrease in the pen pressure value continues, andthe same pen pressure as the internal pen pressure value of the styluspen 3 can be reproduced by using the range of change and the increase ordecrease information.

In the case of outputting the internal pen pressure value of the styluspen 3, for example, as illustrated in FIG. 18, when the internal penpressure value of the stylus pen 3 is represented by changing the unitamount of increase or decrease by 0.1, it is possible to perform thefollowing process when the internal pen pressure value cannotsufficiently keep up with the speed of change even in the case of thesame amount of a pen pressure change.

That is, as illustrated in FIG. 20, the interval between determinationsis reduced in half while the range of increase or decrease of the unitamount of increase or decrease is maintained to 0.1. Accordingly, sincethe speed of change of pen pressure relatively decreases when theinterval between determinations is short, the representation of theinternal pen pressure value is not delayed.

Third Embodiment

Another embodiment of the present invention will be described as followson the basis of FIG. 21 to FIG. 26. Configurations other than thosedescribed in the present embodiment are the same as those of the firstembodiment. For convenience of description, members having the samefunction as the members illustrated in the drawings of the firstembodiment will be designated by the same reference sign, anddescriptions thereof will be omitted.

(Synchronization Operation of Touch Panel Controller and Stylus Pen ofPresent Embodiment)

In the present embodiment, synchronization of the stylus pen 3 and,furthermore, a method that may prevent the pulses of the dedicatedsynchronization signal from not being captured will be described on thebasis of FIG. 21(a) to FIG. 25(c). FIG. 21(a) is a waveform diagramillustrating an input waveform of a synchronization signal received bythe stylus pen in the touch panel system of the present embodiment, andFIG. 21(b) is a waveform diagram illustrating an internal waveform whena reference potential is set at reset timings R1 to R6. FIG. 22(a) is awaveform diagram illustrating an example of a synchronization waveformtransmitted from the touch panel controller, FIG. 22(b) is a waveformdiagram illustrating reset timings R7, R8, and R9 of an input waveformreceived by the stylus pen, and FIG. 22(c) is a waveform diagramillustrating a synchronization waveform when a reference potential isset at the reset timings R7, R8, and R9 illustrated in FIG. 22(b). FIG.23 is a timing chart illustrating output waveforms of the touch panelcontroller in which a fixing period is disposed immediately before asynchronization waveform is output. FIG. 24(a) is a waveform diagramillustrating an example of a synchronization waveform transmitted fromthe touch panel controller, FIG. 24(b) is a waveform diagramillustrating reset timings R11, R12, and R13 of an input waveformreceived by the stylus pen, and FIG. 24(c) is a waveform diagramillustrating a synchronization waveform when a reference potential isset at the reset timings R11, R12, and R13 illustrated in FIG. 24(b).FIG. 25(a) is a diagram illustrating a method for transmitting asynchronization waveform that is transmitted by drive lines DL₁ toDL_(L) of the driver in the touch panel controller, FIG. 25(b) is awaveform diagram illustrating an input waveform received by the styluspen, and FIG. 25(c) is a waveform diagram illustrating a synchronizationwaveform when a reference potential is set after the input waveform isinitially reset in the fixing period illustrated in FIG. 25(b).

When the reset operation is performed at the reset timings R1 to R6where a reference potential is set in a case where the input waveformillustrated in FIG. 21(a) is obtained in the stylus pen 3, the internalwaveform illustrated in FIG. 21(b) is obtained.

In this case, even when the Manchester-coded M-sequence code is used, asillustrated in FIGS. 22(a) to 22(c), the same signal has differentpotentials depending on the timing of the reset operation that sets areference potential, and the difficulty of identifying whether thesynchronization waveform output of the touch panel controller 10 is Highor Low remains the same. That is, it is difficult to find whether asecond peak is High or Low.

Therefore, in the present embodiment, as illustrated in FIG. 23, afixing period F is disposed immediately before the output of thesynchronization waveform to fix the output waveform of the touch panelcontroller 10. The time of fixing is set to a time in which the timingof the reset operation that sets a reference potential in thereception-side stylus pen 3 is included at least once.

Accordingly, a stable potential can be set as a reference potentialbefore the synchronization waveform is output.

Specifically, as illustrated in FIGS. 24(a) and 24(b), the reset timingsR11, R12, and R13 are disposed in the fixing period F to set a referencepotential. Accordingly, as illustrated in FIG. 24(c), the identificationof whether the output of the touch panel controller 10 is High or Low isfacilitated when the synchronization waveform is detected.

As a consequence, as illustrated in FIG. 23, the potential when thereset operation ends becomes a reference potential by disposing thefixing period F before the synchronization waveform is output. Thus, asillustrated in FIGS. 25(a) to 25(c), by disposing the fixing period Fthat is longer than the interval between the reset operations in thestylus pen 3, the reset operation is certainly performed once or moreprior to the synchronization signal detection period in a state wherethe drive potential of the touch panel controller 10 is set, and thewaveform can be shaped in a stable state from the start of thesynchronization signal detection period.

(Continuous Operation of Synchronization of Touch Panel System andStylus Pen and Touch Position Detection)

Continuous operation of the synchronization of the touch panel system 1and the stylus pen 3 having the above configurations and touch positiondetection will be described on the basis of FIG. 26 and FIG. 27. FIG. 26is an operation image diagram illustrating a correspondence between adrive operation of the touch panel controller 10 and a drive operationof the stylus pen 3. FIG. 27 is a diagram illustrating a specific driveoperation in the fixing period illustrated in FIG. 26. In thedescription of FIG. 26 and FIG. 27, the same part as FIG. 13 and FIGS.14(a) to 14(c) of the first embodiment will be briefly described.

The stylus pen 3, as illustrated in FIG. 26, includes thesynchronization signal detection period for detecting thesynchronization signal from the touch panel controller 10 with the sensecircuit 35 and the synchronization signal detector circuit 36, thepreparation period, and the drive mode period during which the pen tipportion 31 is driven by the drive circuit 38.

The synchronization signal detection period, the preparation period, andthe drive mode period are the same as those described in FIG. 13 andFIGS. 14(a) to 14(c).

Meanwhile, the touch panel controller 10 includes the fixing period F,the period during which the drive lines DL₁ to DL_(L) are driven withthe same waveform, the pause period, and a period during which the drivelines DL₁ to DL_(L) are driven and during which a change in charges ofthe electrostatic capacitances is read by the sense lines SL₁ to SL_(L).

The fixing period F is a period for stabilizing a signal level withwhich the stylus pen 3 detects synchronization. Specifically, in thefixing period F, as illustrated in FIG. 21, the drive lines DL₁ toDL_(L) are fixed to either Low or High. Although any of Low and High isfavorable, the drive lines DL₁ to DL_(L) are fixed to Low in the presentembodiment. Thus, the drive lines DL₁ to DL_(L) of the touch panelcontroller 10 have zero potentials. At this time, the drive lineDL_(L+1) for the pen pressure sensor 31 d of the stylus pen 3 is notdriven.

The period during which the drive lines DL₁ to DL_(L) are driven withthe same waveform is a period during which the additionalinformation+the synchronization waveform for the synchronization of thestylus pen 3 are driven. Specifically, as illustrated in FIG. 14(b), thedrive lines DL₁ to DL_(L) are driven with the same waveform.

The pause period is a period during which the stylus pen 3 ends thedetection of synchronization and prepares for driving. Specifically, asillustrated in FIG. 14(b), the pause period is a standby period fordisposing a preparation period during which the stylus pen 3 detects thesynchronization waveform and performs normal driving. Thus, the drivewaveform during the pause period does not have any meaning and iscompletely arbitrary. Therefore, driving may not be performed in thepause period. In addition, the stylus pen 3 does not drive the pen tipportion 31 with the waveforms that correspond to the drive linesDL_(L+1) and DL_(L+2). This duration is not necessary when thepreparation period on the stylus pen 3 side is not necessary.

Next, the period during which the drive lines DL₁ to DL_(L) are drivenand during which a change in charges of the electrostatic capacitancesis read by the sense lines SL₁ to SL_(L) is a normal drive period forposition detection that is performed to obtain data of one face of thetouch panel 2. Specifically, in the normal drive period, as illustratedin FIG. 14(c), driving of the drive lines DL₁ to DL_(L) and reading fromthe sense lines SL₁ to SL_(L) are repeated. Methods for driving includesequential driving and parallel driving. In FIG. 14(c), sequentialdriving is represented so as to facilitate visual understanding of theorder of drive patterns.

The stylus pen 3, when detecting the synchronization waveform, drivesthe pen tip portion 31 with the waveforms that correspond to the drivelines DL_(L+1) and DL_(L+2) which correspond to the outside of the touchpanel 2. That is, the stylus pen 3 outputs waveforms that correspond tothe drive lines DL_(L+1) and DL_(L+2) in accordance with driving of thedrive lines DL₁ to DL_(L) by the touch panel controller 10. In FIG.14(c), colored backgrounds indicate a sense period, that is, a periodduring which a charge signal of an electrostatic capacitance isdetected.

As such, in the touch panel system 1 of the present embodiment, thesense circuit 35 and the synchronization signal detector circuit 36 as asynchronization signal detecting unit of the stylus pen 3 as anelectronic pen detect the amplitude of the synchronization signal byperiodically performing the reset operation to return the received inputwaveform to the reference potential when the synchronization signal onwhich low-frequency components are superimposed is received.Accordingly, it is possible to detect the amplitude of thesynchronization signal inexpensively without using an expensive lowfrequency cut-off filter for the removal of low-frequency componentssuperimposed as noise.

When the reset operation overlaps with a High part of a pulse while thereset operation is arbitrarily performed on the received input waveform,the subsequent signal waveform becomes negative, and thus the positiveHigh part of the pulse cannot be recognized correctly. As a consequence,the synchronization signal may not be captured.

Therefore, in the present embodiment, the synchronization signaltransmission period is configured of the fixing period F during which afixed synchronization signal of which the waveform is fixed to High orLow is transmitted and a pseudorandom sequence waveform period duringwhich the synchronization signal of which the waveform is configured ofa pseudorandom sequence having periodicity such as the M-sequence codeor the Gold sequence code is transmitted. In the fixing period F, thereset operation is performed at least once.

Accordingly, since the input waveform returns to the reference potentialin the fixing period F during which the waveform is fixed to High orLow, it is possible to appropriately determine whether the subsequentpulse is High or Low.

Fourth Embodiment

Still another embodiment of the present invention will be described asfollows on the basis of FIG. 28. Configurations other than thosedescribed in the present embodiment are the same as those of the firstembodiment and the second embodiment. For convenience of description,members having the same function as the members illustrated in thedrawings of the first embodiment and the second embodiment will bedesignated by the same reference sign, and descriptions thereof will beomitted.

In the present embodiment, a case where the touch panel system 1 ismounted on a mobile phone as an electronic device will be described onthe basis of FIG. 28. FIG. 28 is a block diagram illustrating aconfiguration of the mobile phone.

A mobile phone 60 of the present embodiment, as illustrated in FIG. 28,is provided with the touch panel system 1, a display panel 61, anoperating key 62, a loudspeaker 63, a microphone 64, a camera 65, a CPU66, a ROM 67, a RAM 68, and a display controller circuit 69. Theconstituent elements are connected to each other by a data bus.

The touch panel system 1, as described above, includes the touch panel2, the touch panel controller 10 that detects an electrostaticcapacitance or an electrostatic capacitance difference, and the styluspen 3.

The display panel 61 uses the display controller circuit 69 to displayan image stored on the ROM 67 and the RAM 68. In addition, the displaypanel 61 either overlies the touch panel 2 or incorporates the touchpanel 2. It is also possible to cause a touch recognition signal thatindicates the position of a touch on the touch panel 2 and that isgenerated by the touch recognizing unit 17 to play the same role as asignal that indicates that the operating key 62 is operated.

The operating key 62 receives an instruction that is input by a user ofthe mobile phone 60.

The loudspeaker 63 outputs sound that is based on, for example, musicdata stored on the RAM 68.

The microphone 64 receives input of the voice of the user. The mobilephone 60 digitizes the input voice (analog data). Then, the mobile phone60 transmits the digitized voice to a communication opponent (forexample, other mobile phones).

The camera 65 captures an image of a subject in response to the useroperating the operating key 62. The captured image data of the subjectis stored on the RAM 68 or an external memory (for example, a memorycard).

The CPU 66 controls the operation of the touch panel system 1 and themobile phone 60. The CPU 66, for example, executes programs stored onthe ROM 67.

The ROM 67 stores data in a non-volatile manner. In addition, the ROM 67is a ROM such as an erasable programmable read-only memory (EPROM) or aflash memory on which data can be written and deleted. Althoughillustration is not provided in FIG. 28, the mobile phone 60 may beconfigured to be provided with an interface (IF) for wired connection toother electronic devices.

The RAM 68 stores data that is generated by the CPU 66 executing aprogram or data that is input through the operating key 62 in a volatilemanner.

As such, the mobile phone 60 as an electronic device in the presentembodiment is provided with the touch panel system 1. Accordingly, it ispossible to provide the mobile phone 60 as an electronic device that isprovided with the touch panel system 1 which can appropriately detectthe synchronization signal.

CONCLUSION

In order to resolve the above problem, the touch panel system 1 in afirst aspect of the present invention includes a touch pen (stylus pen3), the touch panel 2 that has electrostatic capacitances formed at eachintersection of the K (K is an integer greater than or equal to two)numbers of the first signal lines (horizontal signal lines HL₁ toHL_(K)) and the L (L is an integer satisfying L≧K) numbers of the secondsignal lines (vertical signal lines VL₁ to VL_(L)), and the touch panelcontroller 10. In the touch panel system 1, the touch panel controller10 outputs drive signals that drive the K numbers of the first signallines (horizontal signal lines HL₁ to HL_(K)) or the L numbers of thesecond signal lines (vertical signal lines VL₁ to VL_(L)) from a driveunit (driver 12) through L numbers of drive signal lines (drive linesDL₁ to DL_(L)) and receives input of detection signals from the Knumbers of the first signal lines (horizontal signal lines HL₁ toHL_(K)) or the L numbers of the second signal lines (vertical signallines VL₁ to VL_(L)) detected by a detecting unit (sense amplifier 13)through L numbers of detection signal lines (sense lines SL₁ to SL_(L))on the basis of a change in charges accumulated in the electrostaticcapacitances due to the touch pen (stylus pen 3) when the touch pen(stylus pen 3) touches the touch panel 2. The touch pen (stylus pen 3)is configured of an electronic pen that outputs a quantitativecharacteristic value. The electronic pen (stylus pen 3) produces outputthat indicates that the quantitative characteristic value of theelectronic pen (stylus pen 3) is increased from the characteristic valueof the previous output by using the waveform that corresponds to an(L+1)-th drive signal line (drive line DL_(L+1)) other than the Lnumbers of the drive signal lines (drive lines DL₁ to DL_(L)) and,meanwhile, produces output that indicates that the quantitativecharacteristic value of the electronic pen (stylus pen 3) is decreasedfrom the characteristic value of the previous output by using thewaveform that corresponds to an (L+2)-th drive signal line (drive lineDL_(L+2)) other than the L numbers of the drive signal lines (drivelines DL₁ to DL_(L)). The touch panel controller 10 includes theconversion output unit 19 that converts and outputs the quantitativecharacteristic value by using the sum of the initial value of thequantitative characteristic value and the number of outputs×the unitamount of increase or decrease in the waveform which corresponds to the(L+1)-th drive signal line (drive line DL_(L+1)) or in the waveformwhich corresponds to the (L+2)-th drive signal line (drive lineDL_(L+2)). The representation of L+1 and L+2 is for representing drivesignal lines other than the L numbers or the K numbers of drive signallines, meaning that the drive signals are not actually connected to thetouch panel. Thus, when the actual number of connection lines betweenthe touch panel and the touch panel controller is less than L or K, awaveform that corresponds to an arbitrary drive signal line of thenon-connected drive signal lines may be used.

According to the above configuration, the touch pen is configured of anelectronic pen that outputs a quantitative characteristic value such asa pen pressure level.

In the present invention, the electronic pen produces output thatindicates that the quantitative characteristic value of the electronicpen is increased from the characteristic value of the previous output byusing the waveform that corresponds to the (L+1)-th drive signal lineand, meanwhile, produces output that indicates that the quantitativecharacteristic value of the electronic pen is decreased from thecharacteristic value of the previous output by using the waveform thatcorresponds to the (L+2)-th drive signal line. The touch panelcontroller is provided with the conversion output unit that converts andoutputs the quantitative characteristic value by using the sum of theinitial value of the quantitative characteristic value and the number ofoutput×the unit amount of increase or decrease in the waveform thatcorresponds to the (L+1)-th drive signal line or in the waveform thatcorresponds to the (L+2)-th drive signal line.

That is, in the present invention, the electronic pen outputs only twotypes of information that indicates whether the quantitativecharacteristic value is increased or decreased from the characteristicvalue of the previous output.

The conversion output unit is disposed in the touch panel controller.The conversion output unit converts and outputs a quantitativecharacteristic value by using the sum of the initial value of thequantitative characteristic value and the number of outputs×the unitamount of increase or decrease in the waveform that corresponds to the(L+1)-th drive signal line or in the waveform that corresponds to the(L+2)-th drive signal line.

Accordingly, since only two types of signals related to increase anddecrease are used even when a quantitative characteristic value that hasmany types of information is output, the amount of signals is small, andtransmission can be performed in a short amount of time. In addition,signal processing on the reception side is simplified because it is onlynecessary to obtain the cumulative value of increase and decrease fromthe initial value of the quantitative characteristic value.

Therefore, when the electronic pen that outputs a quantitativecharacteristic value which has many types of information is used, it ispossible to provide the touch panel system that may transmit theinformation simply in a short amount of time.

In the touch panel system 1 in a second aspect of the present invention,the conversion output unit 19 in the touch panel system 1 of the firstaspect preferably includes the unit increase or decrease amount changingunit 19 b that changes the unit amount of increase or decrease.

When, for example, the quantitative characteristic value of theelectronic pen is generated in a short amount of time, a differenceoccurs between the quantitative characteristic value and the actualquantitative characteristic value of the electronic pen if the unitamount of increase or decrease is not increased.

Regarding this point, in the present invention, since the conversionoutput unit is provided with the unit increase or decrease amountchanging unit that changes the unit amount of increase or decrease, theunit increase or decrease amount changing unit can change the unitamount of increase or decrease.

Therefore, it is possible to suppress the occurrence of a differencebetween the quantitative characteristic value and the actualquantitative characteristic value of the electronic pen.

In the touch panel system 1 in a third aspect of the present invention,the unit increase or decrease amount changing unit 19 b in the touchpanel system 1 of the second aspect preferably includes the continuousincrease or decrease changing unit 19 c that increases or decreases theunit amount of increase or decrease when the continuous number ofoutputs in each of the waveform that corresponds to the (L+1)-th drivesignal line (drive line DL_(L+1)) and the waveform that corresponds tothe (L+2)-th drive signal line (drive line DL_(L+2)) is P (P is aninteger greater than or equal to two).

What can be detected by the conversion output unit is only the number ofoutputs in a certain amount of time in the waveform that corresponds tothe (L+1)-th drive signal line or in the waveform that corresponds tothe (L+2)-th drive signal line. Therefore, the problem is how the unitincrease or decrease amount changing unit determines whether to changethe unit amount of increase or decrease.

Regarding this point, in the present invention, the continuous increaseor decrease changing unit is disposed in the unit increase or decreaseamount changing unit to increase or decrease the unit amount of increaseor decrease when the continuous number of outputs in each of thewaveform that corresponds to the (L+1)-th drive signal line and thewaveform that corresponds to the (L+2)-th drive signal line is P (P isan integer greater than or equal to two).

That is, for example, when the number of continuous outputs in thewaveform that corresponds to the (L+1)-th drive signal line is P (P isan integer greater than or equal to two), it is determined that a rapidchange occurs, and the unit amount of increase or decrease is, forexample, doubled. In addition, when, for example, increase furthercontinues, the unit amount of increase or decrease can be furtherincreased.

Accordingly, since the unit amount of increase or decrease can beincreased even if the quantitative characteristic value of theelectronic pen is generated in a short amount of time, it is possible tosuppress the occurrence of a difference between the quantitativecharacteristic value and the actual quantitative characteristic value ofthe electronic pen.

In the touch panel system 1 in a fourth aspect of the present invention,the electronic pen in the touch panel system 1 of any one of the firstto third aspects can include the pen pressure sensor 31 d.

Accordingly, it is possible to detect the pen pressure information thatis an example of a quantitative characteristic value when the electronicpen touches the touch panel.

An electronic device (mobile phone 60) in a fifth aspect of the presentinvention is provided with the touch panel system 1 of any one of thefirst to fourth aspects.

According to the invention, it is possible to provide the electronicdevice that is provided with the touch panel system which may transmitinformation simply in a short amount of time when the electronic penthat outputs a quantitative characteristic value which has many types ofinformation is used.

The present invention is not limited to each embodiment described above.Various modifications can be carried out within the scope of the claims.In addition, an embodiment that is obtained by appropriately combiningtechnical means disclosed in each different embodiment is also includedin the technical scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention can be used in a touch panel system and anelectronic device that detect the position of a touch of a touch pen ona touch panel which has electrostatic capacitances formed at eachintersection of a plurality of first signal lines and a plurality ofsecond signal lines and as an electronic device, for example, can beused in a mobile phone.

REFERENCE SIGNS LIST

-   -   1 TOUCH PANEL SYSTEM    -   2 TOUCH PANEL    -   3 STYLUS PEN (TOUCH PEN, ELECTRONIC PEN)    -   10 TOUCH PANEL CONTROLLER    -   11 MULTIPLEXER    -   12 DRIVER (DRIVE UNIT)    -   13 SENSE AMPLIFIER (DETECTING UNIT)    -   14 TIMING GENERATOR    -   15 AD CONVERTER    -   16 CAPACITANCE DISTRIBUTION CALCULATING UNIT    -   17 TOUCH RECOGNIZING UNIT    -   18 PEN POSITION DETECTING UNIT    -   19 CONVERSION OUTPUT UNIT    -   19 a SUMMATION UNIT    -   19 b UNIT INCREASE OR DECREASE AMOUNT CHANGING UNIT    -   19 c CONTINUOUS INCREASE OR DECREASE CHANGING UNIT    -   30 PEN MAIN BODY    -   30 a HOLDING PORTION    -   31 PEN TIP PORTION    -   31 a PEN TIP COVER    -   31 b PEN TIP AXIS    -   31 c INSULATOR    -   31 d PEN PRESSURE SENSOR    -   32 CONNECTION SWITCH    -   33 CONTROLLER CIRCUIT    -   34 a, 34 b OPERATION CHANGING SWITCH    -   35 SENSE CIRCUIT (SYNCHRONIZATION SIGNAL DETECTING UNIT)    -   36 SYNCHRONIZATION SIGNAL DETECTOR CIRCUIT (SYNCHRONIZATION        SIGNAL DETECTING UNIT)    -   36 a RESET CIRCUIT    -   37 TIMING ADJUSTER CIRCUIT    -   38 DRIVE CIRCUIT    -   39 a FIRST OPERATING SWITCH    -   39 b SECOND OPERATING SWITCH    -   60 MOBILE PHONE (ELECTRONIC DEVICE)    -   61 DISPLAY PANEL    -   62 OPERATING KEY    -   63 LOUDSPEAKER    -   64 MICROPHONE    -   65 CAMERA    -   66 CPU    -   67 ROM    -   68 RAM    -   69 DISPLAY CONTROLLER CIRCUIT    -   C11 to CKL ELECTROSTATIC CAPACITANCE    -   DL₁ to DL_(K) to DL_(L) DRIVE LINE (DRIVE SIGNAL LINE)    -   F FIXING PERIOD    -   HL₁ to HL_(K) HORIZONTAL SIGNAL LINE    -   R RESET TIMING    -   SL₁ to SL_(K) to SL_(L) SENSE LINE (DETECTION SIGNAL LINE)    -   VL₁ to VL_(K) to VL_(L) VERTICAL SIGNAL LINE

The invention claimed is:
 1. A touch panel system comprising: a touchpen; a touch panel that has electrostatic capacitances formed at eachintersection of K (K is an integer greater than or equal to two) numbersof first signal lines and L (L is an integer satisfying L≧K) numbers ofsecond signal lines; and a touch panel controller, wherein the touchpanel controller outputs drive signals that drive the K numbers of thefirst signal lines or the L numbers of the second signal lines from adrive unit through L numbers of drive signal lines and receives input ofdetection signals from the K numbers of the first signal lines or the Lnumbers of the second signal lines detected by a detecting unit throughL numbers of detection signal lines on the basis of a change in chargesthat is accumulated in the electrostatic capacitances due to the touchpen when the touch pen touches the touch panel, the touch pen isconfigured of an electronic pen that outputs a quantitativecharacteristic value, the electronic pen produces output that indicatesthat the quantitative characteristic value of the electronic pen isincreased from the characteristic value of a previous output by using awaveform that corresponds to an (L+1)-th drive signal line other thanthe L numbers of the drive signal lines and, meanwhile, produces outputthat indicates that the quantitative characteristic value of theelectronic pen is decreased from the characteristic value of theprevious output by using a waveform that corresponds to an (L+2)-thdrive signal line other than the L numbers of the drive signal lines,and the touch panel controller includes a conversion output unit thatconverts and outputs the quantitative characteristic value by using thesum of the initial value of the quantitative characteristic value andthe number of outputs×the unit amount of increase or decrease in thewaveform that corresponds to the (L+1)-th drive signal line or in thewaveform that corresponds to the (L+2)-th drive signal line.
 2. Thetouch panel system according to claim 1, wherein the conversion outputunit includes a unit increase or decrease amount changing unit thatchanges the unit amount of increase or decrease.
 3. The touch panelsystem according to claim 2, wherein the unit increase or decreaseamount changing unit includes a continuous increase or decrease changingunit that increases or decreases the unit amount of increase or decreasewhen the continuous number of outputs in each of the waveform whichcorresponds to the (L+1)-th drive signal line and the waveform whichcorresponds to the (L+2)-th drive signal line is P (P is an integergreater than or equal to two).
 4. The touch panel system according toclaim 1, wherein the electronic pen includes a pen pressure sensor. 5.An electronic device comprising: the touch panel system according toclaim 1.